System and method for three-way call detection

ABSTRACT

A system for detecting three-way calls in a monitored telephone conversation includes a speech recognition processor that transcribes the monitored telephone conversation and associates characteristics of the monitored telephone conversation with a transcript thereof, a database to store the transcript and the characteristics associated therewith, and a three-way Call detection processor to analyze the characteristics of the conversation and to detect therefrom the addition of one or more parties to the conversation. The system preferably includes at least one domain-specific language model that the speech recognition processor utilizes to transcribe the conversation. The system may operate in real-time or on previously recorded conversations. A query and retrieval system may be used to retrieve and review call records from the database.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 13/971,292, filed Aug. 20, 2013, which is a continuation applicationof U.S. application Ser. No. 11/706,431, filed Feb. 15, 2007, now U.S.Pat. No. 8,542,802, which are incorporated herein by reference in thenentirety.

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates generally to telephony, and more particularly toa method and system for detecting each time a party is added to apreviously recorded or live telephone call.

Background Art

There is a general need for systems that detect three way calls. Manytypes of systems exist that detect three way calls by measuring certainline characteristics such as voltage fluctuations, noise and otherelectromechanical characteristics.

The purpose of many conventional three way call detection systems is toautomatically disconnect art existing telephone connection whenever athree way call is detected. For example, correctional facilities such asjails and prisons routinely monitor or record telephone conversations ofinmates. Inmates in general are prohibited from making three waytelephone calls because these calls have been found to be made in orderto, for instance, inappropriately contact witnesses or to callindividuals that they would otherwise be prohibited from calling, suchas convicted felons, drug dealers and gang members.

Although most correctional facilities record all telephone calls made byinmates, it is believed that on average only a very small proportion isever monitored by correctional officers. Many correctional facilitiesrecord 2,000 inmate telephone calls a day, so monitoring all telephonecalls or even a large fraction on a regular basis would require too muchpersonnel and would be cost prohibitive. Inmates are aware of this andknow that there is little chance of getting caught making a three waycall. Thus, many make three way calls on a routine basis without beingdetected.

It is desirable in some instances to allow the completion of three waycalls for intelligence gathering purposes because such calls oftencontain evidence of wrongdoing, such as terrorist or criminal activity,or other valuable information. Simply disconnecting an inmate as soon asa three way call is detected could result in the loss of potentiallyvaluable information in those cases where an inmate is suspected ofusing telephones to engage in illegal or improper activity.

BRIEF SUMMARY OF THE INVENTION

It is therefore desirable to be able to search for and retrievetelephone calls that involved three way conversations in order todetermine whether illegal activities were discussed.

It is also desirable to be able to go directly to the point in theconversation where the three way call took place without having tolisten to the entire conversation.

The present invention provides a method and system for the detection,retrieval and playback of three way telephone calls based upon ananalysis of the characteristics and patterns of the content of thetelephone conversation. The invention is designed to provide anefficient means for organizations such as correctional facilities toidentify and monitor the contents of three way conversations. Thepresent invention leverages the discovery that three way conversationsshare a number of characteristics that can readily be detected,measured, analyzed, and input into computer algorithms which can thenreliably determine whether a three way call was placed during aparticular telephone conversation.

Disclosed herein is a system for detecting three-way calls in amonitored telephone conversation. The system includes a speechrecognition processor that transcribes the monitored telephoneconversation and associates at least one characteristic of the monitoredtelephone conversation with a transcript of the monitored telephoneconversation. A database stores at least the transcript of the monitoredtelephone conversation and the at least one characteristic associatedtherewith. In some embodiments of the invention, the database alsostores a recording of the monitored telephone conversation. A three-waycall detection processor analyzes the at least one characteristicassociated with the monitored telephone conversation to detect theaddition of one or more third parties to the monitored telephoneconversation.

The system preferably includes at least one domain-specific languagemodel, such as a language model specific to inmate telephony, that thespeech recognition processor utilizes to transcribe the monitoredtelephone conversation. The system may include multiple domain-specificlanguage models trained for a plurality of ethnic groups, dialects,foreign languages, or other variations in speech and language patterns.Where foreign languages are involved, an optional translation processormay be utilized to translate the monitored telephone conversation or thetranscript thereof.

In some embodiments of the invention, transcription and extraction ofcharacteristics occurs in real-time (that is, while the monitoredtelephone conversation is in progress). Alternatively, the telephoneconversations may be recorded and processed at a later time.

At least some of the characteristics extracted from the monitoredtelephone conversation are indicative of the addition of a third-partyto the conversation, and thus of the establishment of a three-way call.For example, gaps in conversation, dial tones, dial pulses, ring tones,telephone salutations (“hello”), and other verbal and non-verbal cues orpatterns may indicate that a third party has joined the conversation.The three-way call detection processor may detect these characteristicsusing any of a number of call-processing algorithmic, including, withoutlimitation: algorithms that measure the frequency of phrases utteredduring the conversation; algorithms that measure the timing of phrasesuttered during the conversation; algorithms that extract entities fromphrases uttered during the conversation; pattern detection algorithmsthat compare timings of utterances within the conversation with timingsof the at least one characteristic associated therewith; and anycombinations thereof.

Based upon the characteristics and patterns of the monitored telephoneconversation a score may be assigned that is indicative of a likelihoodthat at least one third party was added to the monitored telephoneconversation.

The present invention also provides a method of detecting three-waycalls in a monitored telephone conversation. The method includes:transcribing the monitored telephone conversation; extracting aplurality of characteristics of the monitored telephone conversation;associating the extracted plurality of characteristics with a transcriptof the monitored telephone conversation; utilizing a scoring algorithmto assign a score to the monitored telephone conversation based on theextracted plurality of characteristics, wherein the score is indicativeof a likelihood that at least one third party was added to the monitoredtelephone conversation; and generating information regarding addition ofa third party to the monitored telephone conversation. The scoringalgorithm typically utilizes a scoring function, such as a logisticfunction or a threshold function, to calculate the score, but may alsoutilize an artificial neural network.

The information generated by the method may include tagging thetranscript to identify portions thereof that are pertinent to theaddition of the third party. In other embodiments of the invention, theinformation generated includes timestamps or word or character locationsat which the three-way call likely begins. Of course, the transcript mayalso be associated with a sound recording of the monitored telephoneconversation.

In another aspect of the invention, a method of detecting three-waycalls in a monitored telephone conversation, includes the followingsteps: transcribing the monitored telephone conversation; extractingability of characteristics of the monitored telephone conversation,wherein the plurality of characteristics extracted are indicators of athird party being added to the monitored telephone conversation;calculating a score for the monitored telephone conversation based uponat least two of the plurality of characteristics extracted front themonitored telephone conversation, wherein the score is indicative of alikelihood that at least one third party was added to the monitoredtelephone conversation; and generating information regarding addition ofa third party to the monitored telephone conversation. Preferably, atleast three of the plurality of characteristics, and more preferably atleast four of the plurality of characteristics, will be used tocalculate the score for the monitored telephone conversation.

Also disclosed herein is a query and retrieval system for monitoredtelephone conversations. The query and retrieval system includes adatabase of monitored telephone conversations including a plurality ofcall records. At least some of the call records include a recording ofthe monitored telephone conversation, a transcript of the monitoredtelephone conversation, and a score assigned to the monitored telephoneconversation. The score reflects a likelihood or probability that themonitored telephone conversation included one or more three-way calls,and is based upon one or more characteristics or patterns of themonitored telephone conversation indicative of adding a third partythereto. The system also includes a query interface that accepts userinput of search criteria, including at least a score criterion; aprocessor that retrieves one or more call records from the databasebased upon the search criteria; a selection interface that permits userselection of a call record from the retrieved one or more call records;and an output device that provides synchronized playback andvisualization, respectively, of the recording and transcript included inthe selected call record. The output device optionally provides a visualidentification of the one or more characteristics of the monitoredtelephone conversation indicative of adding a third party thereto. Insome embodiments of the invention, the system further includes aninterface that permits direct navigation to one or more three-way callswithin the monitored telephone conversation.

An advantage of the present invention is that it operates independentlyof any particular type of telephone system, such as VOIP or POTS.

Another advantage of the present invention is that it is not necessaryto Modify existing•telephone equipment or add hardware devices.

Still another advantage of the present invention is that it can detectthree way calls more accurately than previous methods.

Yet another advantage of the present invention is that it can providedetailed information as to the nature and content of the three way call.

Another advantage of the present invention is that it permits one to“jump” directly to the point in the conversation where the three-waycall likely occurred.

Still another advantage is that the present system permits the review ofa large number of recorded phone calls using only a small number ofpersonnel.

A further advantage of the present invention is that it permits thecollection of intelligence information to help uncover inappropriateactivities, such as acts of terrorism.

The foregoing and other aspects, features, details, utilities, andadvantages of the present invention will be apparent from reading thefollowing description and claims, and from reviewing the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a speech recognition systemaccording to an embodiment of the present invention.

FIG. 2 is a flow diagram illustrating a three way call detection methodaccording to an embodiment of the present invention.

FIG. 3 is a drawing illustrating a scoring algorithm according to anembodiment of the present invention.

FIG. 4 is a block diagram illustrating a query and retrieval systemaccording to an embodiment of the present invention.

FIG. 5 is a sample output screen according to an embodiment of the queryand retrieval system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description illustrates the invention with reference to areal world domain, and in particular with respect to correctionalfacilities. However, it should be understood that the practice of theinvention is not limited to any particular domain or application.Rather, it is intended to be more generally applicable to any domainwhere there is a need for three way call detection by examining thecontents and call characteristics of recorded or live telephoneconversations.

Unlike traditional three-way call detection systems, the primary purposeof which is to terminate a telephone conversation upon establishment ofa three-way call, the present invention identifies the three-way calland allows the call to proceed. A user of the system, such as acorrections officer or investigator, may then search for monitored callsduring which at least one three-way call took place, retrieve such acall, and proceed directly to the point where a third party was added,for example to gather intelligence or evidence of inappropriate conduct.

The following is a portrayal of one example of a typical sequence ofevents that might occur when an inmate or similar person makes a threeway call:

1. The inmate first places a call to a telephone number that is notblocked or otherwise restricted by the correctional facility. Therecipient of the call answers the phone.

2. At some point during the telephone conversation, the inmate asks therecipient to place a three may call. When making this request, theinmate might dictate a telephone number or mention the name ororganization of the third party to call.

3. The recipient then might put the inmate on hold while the call isbeing made. Alternatively, the recipient might use a separate phone(e.g., a separate cell phone) to place the three way call. Certain callcharacteristics suggestive of a three-way call, such as a gap in speechor a series of dial tones or pulses, may be observed, and may possiblybe followed by a ring tone.

4. The third party answers the phone and commences conversing with theinmate. The third party will typically answer with a phrase commonlyused when answering the telephone such as “hello,” “hi,” or anothersalutation or greeting, or stating the name of a person or organization.At this point a speaker recognition (or speaker turn) component of thespeech recognition system may detect that a third and previouslyundetected speaker has been added to the call. It is important to rotethat the addition of a third and previously undetected speaker in theconversation by itself is not dispositive of a three way call. It couldsimply be another member of the household of the original recipient ofthe call.

5. After a while the inmate or three way call recipient decides toterminate the three way call. At this point the inmate may do one ofthree things: terminate the original call, continue to converse with theoriginal receipt make another three way call.

6. if another three the same way call is made, the same or similarsequence of events from (1) through (5) applies.

The present invention focuses on an analyzes the three way callcharacteristics described above (e.g., verbal and non-verbal cues, suchas telephone numbers, names of people or organization to call,salutations, dial tones, dial pulses, ring tones, gaps in conversation,speaker turns/recognition of new speakers, and other three way callcharacteristics). A speed recognition processor, in combination with aplurality of other algorithms and processors, searches the monitoredcall for clues that would indicate the addition of one or more thirdparties to a telephone conversation, while a three-way call detectionprocessor evaluates the clues to determine a probability that the callincluded at least one three-way call.

FIG. 1 illustrates a block diagram of a speech recognition system 100according to an embodiment of the present invention. The speechrecognition system 100 may be software-implemented (e.g., a softwareprogram executed by one or more computer systems or speech recognitionprocessors), hardware-implemented (e.g., as a series of instructionsstored in one or more solid-state devices), or a combination of both. Itshould also be understood that multiple instances of the speechrecognition system 100 may be simultaneously executed on a singlecomputer or on multiple computers.

In FIG. 1, the speech recognition process 104 processes previouslyrecorded telephone conversations 106 or ongoing telephone conversations102, which are referred to interchangeably herein as “monitoredtelephone conversations,” “telephone conversations,” “conversations,” orsimply “calls.” The speech recognition process 104 performs a number offunctions, of which one is converting the spoken audio to text(transcription). In doing so, the speech recognition process utilizes atleast one language model 108. When transcribing speech to text, it isdesirable to ensure that the language model used is domain-specific,which enhances the accuracy of the transcription process. A“domain-specific” language model is a language model that accuratelyreflects the linguistic nuances of the participants of a telephoneconversation, for example a language model that is domain-specific toUrinate telephony. Preferably, therefore, at least one domain specificlanguage model is used by the system in transcribing the audio of themonitored telephone conversation to text.

In some embodiments of the invention, it is contemplated that multipledomain-specific language models may be used, which may be trained for aplurality of ethnic groups, a plurality of regional dialects, or otherlanguage differences. Using multiple domain-specific language models hasbeen shown to significantly improve speech recognition and transcriptionaccuracy. It is also contemplated that, in instances where foreignlanguages are spoken, multiple domain specific language models trainedfor a plurality of foreign languages may be used. Further, a translationprocessor may be utilized to translate the transcript of the monitoredtelephone conversation from a first language to a second language (e.g.,to translate a conversation in Spanish into English).

In addition to converting spoken audio to text, the speech recognitionprocess extracts a number of verbal and nonverbal characteristics fromthe telephone conversation. These include, but are not limited to,speaker turns (e.g., as determined by voice-recognition of the speakersin the telephone conversation): gaps in audio; dial, pulse, and ringtones; verbal cues (e.g., mentions of telephone numbers, mentions ofpeople or organizations to call, or telephone salutations such as“hello”); speech and phraseology patterns; and tinting information thatincludes the beginning and end times (e.g., as measured in eitherseconds or milliseconds front the beginning of the telephoneconversation) of utterances, audio gaps, dial pulse and ring tones, andspeaker turns. The characteristics are preferably associated with thetranscript of the monitored telephone conversation.

Once the speech recognition process has completed processing thetelephone conversation, it outputs the results to a file. One suitableformat for the output file is an XML file 112. The output file is thenprocessed by an output processor 110 that extracts each component fromthe XML file and inserts it as a call record into a multimedia database114, for example as a binary large object (BLOB). That is, asillustrated in FIG. 1, the multimedia database stores the transcript ofthe monitored telephone conversation, the associated characteristics ofthe monitored telephone conversation, and, in some embodiments of theinvention, a sound recording of the monitored telephone conversation.The sound recording may, of course, be analog or digital. It is alsowithin the spirit and scope of the present invention to store therecordings of the monitored telephone conversation in a file systemexternal to the multimedia database, in which case the multimediadatabase preferably includes appropriate references to the external filesystem. The telephone conversation is now ready for three way calldetection.

FIG. 2 illustrates a flow chart diagram of a three way call detectionmethod 200 according to an embodiment of the present invention. As withthe speech recognition method illustrated in FIG. 1 and described above,it is contemplated that the three-way call detection method illustratedin FIG. 2 and described below may be hardware-implemented,software-implemented, or both hardware- and software-implemented. It isalso contemplated that multiple instances of the three-way calldetection method may run simultaneously on one or more computers or byone or more three-way call detection processors.

In the embodiment illustrated in FIG. 2, the three way call detectionmethod begins by utilizing a call retrieval process 202 to retrieve apreviously unprocessed call from the multimedia database 114. Thetranscribed text, as well as information regarding the associated callcharacteristics, may be forwarded to the call processing algorithms 210.The call processing algorithms employ a variety of techniques including,but not limited to: entity extraction (e.g., algorithms that extractpeople, places, organizations, telephone numbers and other entities fromthe transcribed text); algorithms that measure the frequency of phrasesuttered during the call; algorithms that measure the timing of phrasesuttered during the call; pattern detection techniques that compare thetiming of phrases and entities uttered with the timing of extractedtelephone conversation characteristics such as gaps in speech, dialtones, pulses and speaker turns; and any combinations thereof. Forexample, one call processing algorithm may compare the timing of theutterance of a telephone number with the timing of a gap in theconversation; if the two are close in time (e.g., a telephone number isuttered and, a few seconds later, a gap in the conversation occurs), itmay indicate establishment of a three-way call.

The call processing algorithms seek characteristics or patternsindicative of a three-way call. If any characteristics or patternsindicative of a three-way call are identified at a particular point inthe telephone conversation, the call processing algorithms may output amatrix of the identified characteristics and/or patterns, along withtiming information and a weighting structure that weights each patternand characteristic with respect to its relative importance as acharacteristic, or pattern indicative of a three-way call. For example,a nap in the conversation may have a lower weight than an utterance of atelephone number followed by a gap in the conversation, which may have alower weight than an utterance of a telephone number followed by a gapin the conversation in which dial tones are detected, which may have alower weight than an utterance of a telephone number followed by a gapin the conversation in which dial tones are detected and after which anew speaker is identified by the speech recognition processor. Theoutput matrix is then forwarded to the scoring algorithm 208. If nothree way call characteristics are identified, control is returned tothe call retrieval process, which then retrieves the next unprocessedtelephone conversation from the multimedia database.

The scoring algorithm 208 then computes a score based on the outputmatrix of the extracted call characteristics and patterns. The score isindicative of a likelihood or probability that at least one third partywas added to the monitored telephone conversation. In some embodimentsof the invention, the score is computed as follows:

${S = {\sum\limits_{i = l}^{n}\;{w_{i}x_{i}}}},$where S is the interim score, n is the number of characteristics andpatterns in the output matrix of the call processing algorithms 210,w_(i) is the weight of the i^(th) characteristic or pattern in thematrix, and x_(i) is the i^(th) characteristic or pattern in the matrix.Note that x_(i) can be represented by binary, integer, or continuousvalues. In other embodiments of the invention, the scoring algorithm maycalculate the value of S using an associative artificial neural network,such as an associative network, for example Kohonen networks.

The interim score S may optionally be further refined by the use of alogistic function to produce values of between zero and one as follows:

${{SF} = \frac{1}{1 + {\mathbb{e}}^{- S}}},$where SF is the final score. A graphical representation of the twoscoring equations outlined above is illustrated in FIG. 3, where F(S) isrepresented by the preceding equation. Also in FIG. 3, a bias is addedto the calculation of S. If the interim score S is not further refined,then the interim score S becomes the final score SF.

Referring once again to FIG. 2, after the final score has beencalculated, it is determined whether it exceeds a minimum requirement toindicate that a three way call took place. For example, the final scoremay be compared to a threshold in order to minimize the potential forfalse positives (e.g., identifications of three-way calls where nothree-way calls in fact occurred). If the threshold is exceeded, controlis passed to the tagging algorithm 206, which will be further describedbelow. Otherwise, if the end of the current call has been reached,control is passed back to the call retrieval process 202. If the end ofthe call has not been reached, control is passed back to the callprocessing algorithms 210, which will then continue processing the call.

Upon successful detection of a three way call, information regarding theaddition of a third party to the telephone conversation may begenerated. For example, the tagging process 206 may tag the telephoneconversation being processed as including at least one three-way call,and may also tag each phrase, pattern, or point in the transcript thatis pertinent to a three way call. The tags may then be added to themultimedia database 114 as part of the call record along with the finalscore for the telephone conversation output by the scoring algorithm.

The tagging process 206 then passes control to the synchronizationprocess 204. The synchronization process identifies the likely beginningof the detected three way call and updates the call record produced bythe tagging process 206 with information regarding the likely beginningof the detected three-way call. For example, the synchronization process204 may add a time stamp or other timing information that identifies thenumber of seconds from the beginning of the call at which the three-waycall took place. The synchronization process 204 may also addinformation about how many words or characters into the transcript thethree way call occurred. The multimedia database 114 may also be updatedto include at least one index of detected three-way calls and thecharacteristics associated with those calls.

If the end of the call has been reached, control is returned to the callretrieval process. Otherwise, control is returned to the call processingalgorithms.

FIG. 4 is a block diagram of a generalized query and retrieval system400 according to an embodiment of the present invention that may be usedto retrieve records from the multimedia database 114, and in particularmay be used to retrieve records of three-way calls from the multimediadatabase 114. The call browser and display 402 of FIG. 4 may be used toquery and retrieve detected three way calls from the multimedia database114. The call browser and display 402 preferably accepts queries basedupon scores. For example, a user may request calls having scores thatfall within a particular range or that exceed a particular threshold. Itis contemplated, however, that the call browser and display 402 mayaccept any type of criteria on which to search the multimedia database114 (e.g., call dates, call times, or the identity of a party to thecall). A suitably-programmed processor may retrieve one or more callrecords meeting the specified criteria from the multimedia database 114.

FIG. 5 shows a sample output screen 500 of a query and retrieval systemaccording to the present invention. Panel 502 displays the call recordsretrieved in response to a particular query and permits a user to selectone of the retrieved call records. Panel 504 shows the transcript of theselected call record. The “Play Call” button 506 will initiate playbackof the recording of the selected telephone conversation. Preferably, thequery and retrieval system includes an output device capable ofproviding synchronized playback and visualization, respectively, of therecording and transcript of the selected telephone conversation. Forexample, as the audio recording of the call is played back, a movinghighlight may track through the transcript in panel 504.

The output device further preferably provides a visual identification ofthe one or more characteristics of the monitored telephone conversationthat are indicative of the establishment of a three-way call. Forexample, the transcript in panel 504 may be highlighted or otherwiseflagged at the point where the three-way call was established orthroughout the three-way call (e.g., the entire portion of thetranscript covering the three-way call may be bold faced). Similarly,the panel 508 may show a time stamp 510 of when in the call thethree-way call was established, and, optionally, when it was terminated.In some embodiments of the invention, the time stamp 510 may be used tonavigate directly (or “jump”) to the point in the conversation where thethree-way call took place, thereby advantageously permitting lawenforcement officials to review only the portion of the conversationthat is of particular interest.

Although only a few illustrative embodiments of this invention have beendescribed above with a certain degree of particularity, those skilled inthe art could make numerous alterations to the disclosed embodimentswithout departing from the spirit or scope of this invention. It isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative only andnot limiting. Changes in detail or structure may be made withoutdeparting front the spirit of the invention as defined in the appendedclaims.

What is claimed is:
 1. A system for detecting a presence of a thirdparty participating in a monitored telephone conversation, the systemcomprising: a speech recognition module configured to detect a firstcharacteristic of the monitored telephone conversation and a secondcharacteristic of the monitored telephone conversation; a speechanalysis module configured to calculate a three-way calling score forthe monitored telephone conversation, the calculating including:assigning a first score of the first characteristic based on apredefined importance of the first characteristic; assigning a secondscore of the second characteristic based on a predefined importance ofthe second characteristic; and calculating the three-way calling scoreby summing the first score and the second score; and a three-way calldetection module configured to detect the presence of the third partybased on a comparison of the three-way calling score to a predeterminedthreshold.
 2. The system of claim 1, further comprising a database thatstores the first score and the second score.
 3. The system of claim 1,wherein the calculating further includes normalizing the sum to a valuebetween 0 and 1 using a refining function.
 4. The system of claim 3,wherein the refining function includes: calculating a first value as thenatural log of the negative of the sum; adding 1 to the first value toobtain a second value; and inverting the second value.
 5. The system ofclaim 1, wherein the first characteristic represents the detection of aspoken phone number during the monitored telephone conversation, andwherein the second characteristic represents a gap in speech during themonitored telephone conversation.
 6. The system of claim 5, wherein avalue of the second score increases according to a proximity of thesecond characteristic to the first characteristic within the monitoredtelephone conversation.
 7. A method for detecting a presence of a thirdparty participating in a monitored telephone conversation, the methodcomprising: detecting a first characteristic of the monitored telephoneconversation and a second characteristic of the monitored telephoneconversation; calculating a three-way calling score for the monitoredtelephone conversation, the calculating including: assigning a firstscore of the first characteristic based on a predefined importance ofthe first characteristic; assigning a second score of the secondcharacteristic based on a predefined importance of the secondcharacteristic; and calculating the three-way calling score by summingthe first score and the second score; and detecting the presence of thethird party based on a comparison of the three-way calling score to apredetermined threshold.
 8. The method of claim 7, further comprisingstoring the first score and the second score in a database.
 9. Themethod of claim 7, wherein the calculating further includes normalizingthe sum to a value between 0 and 1 using a refining function.
 10. Themethod of claim 9, wherein the refining function includes: calculating afirst value as the natural log of the negative of the sum; adding 1 tothe first value to obtain a second value; and inverting the secondvalue.
 11. The method of claim 7, wherein the first characteristicrepresents the detection of a spoken phone number during the monitoredtelephone conversation, and wherein the second characteristic representsa gap in speech during the monitored telephone conversation.
 12. Themethod of claim 11, wherein a value of the second score increasesaccording to a proximity of the second characteristic to the firstcharacteristic within the monitored telephone conversation.
 13. A systemfor detecting a presence of a third party participating in a monitoredtelephone conversation, the system comprising: a speech recognitionmodule configured to detect a plurality of characteristics of themonitored telephone conversation; a scoring module configured to scorethe monitored telephone conversation based on the plurality ofcharacteristics, the scoring including: accessing a scoring databasethat stores scores of detectable characteristics; looking up acorresponding score for each of the plurality of characteristics; andassigning each of the plurality of characteristics the correspondingscores; a three-way call detection module configured to detect thepresence of the third party based on a comparison of the score to apredetermined threshold; and a tagging module configured to associateadditional information with the monitored telephone call following thedetection of the presence of the third party.
 14. The system of claim13, wherein the scoring module is further configured to score themonitored telephone conversation by: summing the assigned scores. 15.The system of claim 13, wherein the scoring module is configured toscore the monitored telephone conversation, and the three-way calldetection module is configured to compare the score to the predeterminedthreshold, after each detection by the speech recognition module of oneof the plurality of characteristics of the monitored telephoneconversation.
 16. The system of claim 13, wherein the tagging module isconfigured to add a tag identifying an approximate starting point of thepresence of the third party in the monitored telephone conversation. 17.The system of claim 15, wherein the tagging module is configured to adda tag identifying an approximate starting point of the presence of thethird party in the monitored telephone conversation based on a firstscore to exceed the predetermined threshold.
 18. The system of claim 16,wherein the approximate starting point is represented by a timestampindicating a number of seconds into the monitored telephone call inwhich the presence of the third party was detected.